Improvement in iron bridges



' .entitled gums @HMM @with MAHLON MILLER, OF CLEVELAND, OHIO.

Lene/r3 Patent N0.`1o3,911, @ma .me 7, 1ero.

IMPROVIElIi/IEITI'.' IN' IRON BRIDGES.

` 'The 'Schedule referred to in thse Letters Patent and making .part of the Same To all'. wle-om it may concern Be it known that I, MAHLON MILLER, of Oleve? land, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Iron Bridges; and I do hereby declare thatv the following is a full and complete description of the same, reference being had to the accompanying drawing making part of this specification.

This invention relates to tubular arches forbridges,

roofs, &c. as hereinafter more fully described.

Description. y In tig. 1, A represents an arch, which consists of la pair of side plates B B, tig. 3, and a central plate,

G,:the length, thickness, and curvature of which being as the'strength and span of' the arch may require.

The upper and lower plates D E, constituting the upper and lower vside of the arch, have on their inner surfaces grooves or channels c, into which are received the edges'of the side and central plates, as shown in the drawing. i

By this means the several plates are securely held in a vertical position, and in iriimediate and close coutact with theupper and lowerplates, forming a strong and ,durable joint of simple and easy construction.

The upper and lower plates are secured in their contact with the vertical plates 'by means of the suspension-rods F, the upper ends of which are bifurcated, thereby forming a pair of bolts, G, which penetrate the arch, and are secured on the upper end by nuts a, whereas the lower ends ofthe rods depend, and thereto is attached the c'ord or Stringer H, on which the door or roadway is supported.

The ends of the arch are received into and rest upon abutment-shoes I, and are secured therein by the cord-bolts J.

It will be observed that the upper plate D of the arch is fluted or channeled, whereby is formed acentral rib, b, along the arch line. .This form of the plate is intended to be used when extra strength is required for the arch, and for which like purpose the Vlower plate may be constructed in the s'ame manner,

as shown in iig. 6. l

=11`or ordinary purpose sor when no extraordinary strainis -to be exerted upon the arch, both the upper, v

and lower plates `may be plain, like unto the lower one in tig. 1, and which -is morefully shown in fig. 5.

' Eig. 4 shows a modification of the above, in which it will be seen that the upper and lower plates combine the channel land plain -form, all. of which, how.. ever, embrace 'the' same principle of construction and adaptation of the several plates to each other by means of grooves on the inner faces` of the upper and Y lower plates for the admission of the edges ofthe side cr vertical plates, as above4 described. In order to obtain more lateral strength to the arc and keep the several plates in their articulationsquarc with each other,a fillet or box, fig. 7, is introduced into each tubular section of the arch, which, exactly tting the inside, as shown at d, iig, 5, serves as' a brace, thereby preventing the sides .from swerving from their rectangular relation .to the upper and lower plates. 1

VA box or fillet of this Vnature may be placedaround each bolt, or around -as many of them asunay be d esired. l

In fig. 7 one only is shown, whereas the holt in the adjoining tubular section is' shown as being without such fillet or box.

Claim.

What I claim as my improvement, and dcsireto secure by Letters Patent, is-

The plates D E, provided with grooves c and plates B B, with or without central plate or plates,-in combination with the fillet or box d, and bolts G, conv 

